Extreme weather events were analyzed based on the meteorological data from the year of 1967 to 2007 for Yamaguchi, Japan. The responses from landscape trees were also investigated mainly by the analysis of image pixel...Extreme weather events were analyzed based on the meteorological data from the year of 1967 to 2007 for Yamaguchi, Japan. The responses from landscape trees were also investigated mainly by the analysis of image pixel and spectral reflectance. Results show that after the dry, hot and windy summer in 2007, many landscape trees in Yamaguchi City tended to respond the extreme weather events by reducing their leaf surface area and receiving less radiation energy. Premature leaf discoloration or defoliation appeared on some landscape tree species and leaf necrosis occurred on tip and margin of many Kousa dogwood (Cornus kousa) trees at unfavorable sites. Described by image pixel analysis method, the leaf necrotic area percentage (LNAP) of sampled dogwood trees averaged 41.6% and the sampled Sasanqua camellia (Camelia sasanqua) tree also showed fewer flowers in flower season of 2007 than that in 2006. By differential analysis of partial discolored crown, it presented a logistic differential equation of crown color for sweet gum (Liquidambar styraciflua) trees. It suggested that the persistent higher temperature and lower precipitation could be injurious to the sensitive landscape trees at poor sites, even in relative humid area like Yamaguchi.展开更多
A new photodetector--bipolar junction photogate transistor is presented for CMOS image sensor and its analytical model is also established.With the technical parameter of the 0.6μm CMOS process,the bipolar junction p...A new photodetector--bipolar junction photogate transistor is presented for CMOS image sensor and its analytical model is also established.With the technical parameter of the 0.6μm CMOS process,the bipolar junction photogate transistor is analyzed and simulated.The simulated results illustrate that the bipolar junction photogate transistor has the similar characteristics of the traditional photogate transistor.The photocurrent density of the bipolar junction photogate transistor increases exponentially with the incidence light power due to introducing the injection p+n junction.Its characteristic of blue response is rather improved compared to the traditional photogate transistor that benefits to increase the color photograph made up of the red,the green,and the blue.展开更多
In this study,we have developed a high-sensitivity,near-infrared photodetector based on PdSe2/GaAs heterojunction,which was made by transferring a multilayered PdSe2 film onto a planar GaAs.The as-fabricated PdSe2/GaA...In this study,we have developed a high-sensitivity,near-infrared photodetector based on PdSe2/GaAs heterojunction,which was made by transferring a multilayered PdSe2 film onto a planar GaAs.The as-fabricated PdSe2/GaAs heterojunction device exhibited obvious photovoltaic behavior to 808 nm illumination,indicating that the near-infrared photodetector can be used as a self-driven device without external power supply.Further device analysis showed that the hybrid heterojunction exhibited a high on/off ratio of 1.16×10^5 measured at 808 nm under zero bias voltage.The responsivity and specific detectivity of photodetector were estimated to be 171.34 mA/W and 2.36×10^11 Jones,respectively.Moreover,the device showed excellent stability and reliable repeatability.After 2 months,the photoelectric characteristics of the near-infrared photodetector hardly degrade in air,attributable to the good stability of the PdSe2.Finally,the PdSe2/GaAs-based heterojunction device can also function as a near-infrared light sensor.展开更多
Compared to a scalar pressure sensor, a vector sensor can provide a higher signal-to-noise ratio （SNR） signal and more detailed intbrmation on the sound field. Study on vector sensors and their applications have bec...Compared to a scalar pressure sensor, a vector sensor can provide a higher signal-to-noise ratio （SNR） signal and more detailed intbrmation on the sound field. Study on vector sensors and their applications have become a hot topic. Research on the representation of a vector field is highly relevant for extending the scope of vector sensor technology. This paper discusses the range-frequency distribution of the vector field due to a broadband acoustic source moving in a shallow-water waveguide as the self noise of a surface ship, and the vector extension of the waveguide impulse response measured over a limited frequency range using an active source of known waveform. From theory analysis and numerical simulation, the range-frequency representation of a vector field exhibits an interference structure qualitatively similar to that of the corresponding pressure field but, being quantitatively different, provides additional information on the waveguide, especially through the vertical component. For the range-frequency representation, physical quantities that can better exhibit the interference characteristics of the wavegaide are the products of pressure and particle velocity and of the pressure and pressure gradient. An image processing method to effectively detect and isolate the individual striations from an interference structure was reviewed briefly. The representation of the vector impulse response was discussed according to two different measurement systems, also known as particle velocity and pressure gradient. The vector impulse response representation can not only provide additional information from pressure only but even more than that of the range-frequency representation.展开更多
This study was aimed at investigating the sampling strategies for 2 types of figures: 3-D cubes and human faces. The research was focused on: (a) from where the sampling process started; (b) in what order the figures&...This study was aimed at investigating the sampling strategies for 2 types of figures: 3-D cubes and human faces. The research was focused on: (a) from where the sampling process started; (b) in what order the figures' features were sampled. The study consisted of 2 experiments: (a) sampling strategies for 3-D cubes; (b) sampling strategies for human faces. The results showed that: (a), for 3-D cubes, the first sampling was mostly located at the outline parts, rarely at the center part; while for human faces, the first sampling was mostly located at the hair and outline parts, rarely at the mouth or cheek parts, in most cases, the first sampling-position had no significant effects on cognitive performance and that (b), the sampling order, both for 3-D cubes and for human faces, was determined by the degree of difference among the sampled-features.展开更多
Manganese enhanced magnetic resonance im- aging (MRI) is a novel neuroimaging technique that can be used in vivo to trace neuronal tract and to study brain func- tions dynamically. In this study, manganese enhanced MR...Manganese enhanced magnetic resonance im- aging (MRI) is a novel neuroimaging technique that can be used in vivo to trace neuronal tract and to study brain func- tions dynamically. In this study, manganese enhanced MRI was used to trace the neuronal tracts between the laminar structures of the olfactory bulb (OB) in rat and to study the so-called “calcium overload” phenomenon in a rat model of cerebral ischemia. High spatial resolution images of the OB were obtained and used to measure the transportation rate of Mn2+ among the laminar structures of the OB, which was shown to be approximately 0.2 mm/h under resting condition. In the rat focal ischemia study, it was found that the total area of brain regions with Mn2+ accumulation (representing brain regions with calcium overload) was only 55%±15% of the area of the ischemic brain regions shown by diffu- sion-weighted imaging (DWI). Manganese enhanced MRI might be more accurate than DWI in detecting the ischemic core at the early stage of experimental cerebral ischemia.展开更多
Nanocapsule-based targeted delivery and stimulus-responsive release can increase drug effectiveness, while reducing the side effects of the drug. However, difficulties in the scale-up synthesis, fast burst release, an...Nanocapsule-based targeted delivery and stimulus-responsive release can increase drug effectiveness, while reducing the side effects of the drug. However, difficulties in the scale-up synthesis, fast burst release, and low degradability, could hamper the translation of drug nanocapsules from lab to clinic. Here we have controllably functionalized the biodegradable and widely available polysuccinimide, in order to obtain an amphiphilic poly（amino acid）. Using this polymer, we designed nanocapsules （〈 100 nm） for hydrophobic drug delivery, which could facilitate tumor targeting, hydrogen bond-based pH-responsive release, and real-time fluorescence tracking, in the second near-infrared region. This method is versatile, eco-friendly, and easy to scale up at low costs. In addition, this system can carry a cocktail of drugs, obtained by loading multiple anticancer drugs to the same vehicle. Our nanocapsules were observed to be stable in blood vessels （pH = 7.4）, and the pH-responsive release （pH = 5.0 in lysosome） was sustained. The chemotherapy results in tumor-xenografted mice suggested that our nanocapsule was safe and efficient, and may be a useful tool for drug delivery.展开更多
文摘Extreme weather events were analyzed based on the meteorological data from the year of 1967 to 2007 for Yamaguchi, Japan. The responses from landscape trees were also investigated mainly by the analysis of image pixel and spectral reflectance. Results show that after the dry, hot and windy summer in 2007, many landscape trees in Yamaguchi City tended to respond the extreme weather events by reducing their leaf surface area and receiving less radiation energy. Premature leaf discoloration or defoliation appeared on some landscape tree species and leaf necrosis occurred on tip and margin of many Kousa dogwood (Cornus kousa) trees at unfavorable sites. Described by image pixel analysis method, the leaf necrotic area percentage (LNAP) of sampled dogwood trees averaged 41.6% and the sampled Sasanqua camellia (Camelia sasanqua) tree also showed fewer flowers in flower season of 2007 than that in 2006. By differential analysis of partial discolored crown, it presented a logistic differential equation of crown color for sweet gum (Liquidambar styraciflua) trees. It suggested that the persistent higher temperature and lower precipitation could be injurious to the sensitive landscape trees at poor sites, even in relative humid area like Yamaguchi.
文摘A new photodetector--bipolar junction photogate transistor is presented for CMOS image sensor and its analytical model is also established.With the technical parameter of the 0.6μm CMOS process,the bipolar junction photogate transistor is analyzed and simulated.The simulated results illustrate that the bipolar junction photogate transistor has the similar characteristics of the traditional photogate transistor.The photocurrent density of the bipolar junction photogate transistor increases exponentially with the incidence light power due to introducing the injection p+n junction.Its characteristic of blue response is rather improved compared to the traditional photogate transistor that benefits to increase the color photograph made up of the red,the green,and the blue.
基金supported by the National Natural Science Foundation of China(No.61575059,No.61675062,No.21501038)the Fundamental Research Funds for the Central Universities(No.JZ2018HGPB0275,No.JZ2018HGTA0220,and No.JZ2018HGXC0001).
文摘In this study,we have developed a high-sensitivity,near-infrared photodetector based on PdSe2/GaAs heterojunction,which was made by transferring a multilayered PdSe2 film onto a planar GaAs.The as-fabricated PdSe2/GaAs heterojunction device exhibited obvious photovoltaic behavior to 808 nm illumination,indicating that the near-infrared photodetector can be used as a self-driven device without external power supply.Further device analysis showed that the hybrid heterojunction exhibited a high on/off ratio of 1.16×10^5 measured at 808 nm under zero bias voltage.The responsivity and specific detectivity of photodetector were estimated to be 171.34 mA/W and 2.36×10^11 Jones,respectively.Moreover,the device showed excellent stability and reliable repeatability.After 2 months,the photoelectric characteristics of the near-infrared photodetector hardly degrade in air,attributable to the good stability of the PdSe2.Finally,the PdSe2/GaAs-based heterojunction device can also function as a near-infrared light sensor.
基金Supported by Office of Naval Research grant N00014-07-1-1069the National Nature Science Foundation of China grant 50979019the Belgian National Fund for Scientific Research (F.R.S. - FNRS)
文摘Compared to a scalar pressure sensor, a vector sensor can provide a higher signal-to-noise ratio （SNR） signal and more detailed intbrmation on the sound field. Study on vector sensors and their applications have become a hot topic. Research on the representation of a vector field is highly relevant for extending the scope of vector sensor technology. This paper discusses the range-frequency distribution of the vector field due to a broadband acoustic source moving in a shallow-water waveguide as the self noise of a surface ship, and the vector extension of the waveguide impulse response measured over a limited frequency range using an active source of known waveform. From theory analysis and numerical simulation, the range-frequency representation of a vector field exhibits an interference structure qualitatively similar to that of the corresponding pressure field but, being quantitatively different, provides additional information on the waveguide, especially through the vertical component. For the range-frequency representation, physical quantities that can better exhibit the interference characteristics of the wavegaide are the products of pressure and particle velocity and of the pressure and pressure gradient. An image processing method to effectively detect and isolate the individual striations from an interference structure was reviewed briefly. The representation of the vector impulse response was discussed according to two different measurement systems, also known as particle velocity and pressure gradient. The vector impulse response representation can not only provide additional information from pressure only but even more than that of the range-frequency representation.
基金Project (No. 39670262) supported by the National Natural Science Foundation of Chinathe International Scholar Exchange Fellowship Program (2000) of the Korea Foundation For Advanced Studies
文摘This study was aimed at investigating the sampling strategies for 2 types of figures: 3-D cubes and human faces. The research was focused on: (a) from where the sampling process started; (b) in what order the figures' features were sampled. The study consisted of 2 experiments: (a) sampling strategies for 3-D cubes; (b) sampling strategies for human faces. The results showed that: (a), for 3-D cubes, the first sampling was mostly located at the outline parts, rarely at the center part; while for human faces, the first sampling was mostly located at the hair and outline parts, rarely at the mouth or cheek parts, in most cases, the first sampling-position had no significant effects on cognitive performance and that (b), the sampling order, both for 3-D cubes and for human faces, was determined by the degree of difference among the sampled-features.
文摘Manganese enhanced magnetic resonance im- aging (MRI) is a novel neuroimaging technique that can be used in vivo to trace neuronal tract and to study brain func- tions dynamically. In this study, manganese enhanced MRI was used to trace the neuronal tracts between the laminar structures of the olfactory bulb (OB) in rat and to study the so-called “calcium overload” phenomenon in a rat model of cerebral ischemia. High spatial resolution images of the OB were obtained and used to measure the transportation rate of Mn2+ among the laminar structures of the OB, which was shown to be approximately 0.2 mm/h under resting condition. In the rat focal ischemia study, it was found that the total area of brain regions with Mn2+ accumulation (representing brain regions with calcium overload) was only 55%±15% of the area of the ischemic brain regions shown by diffu- sion-weighted imaging (DWI). Manganese enhanced MRI might be more accurate than DWI in detecting the ischemic core at the early stage of experimental cerebral ischemia.
文摘Nanocapsule-based targeted delivery and stimulus-responsive release can increase drug effectiveness, while reducing the side effects of the drug. However, difficulties in the scale-up synthesis, fast burst release, and low degradability, could hamper the translation of drug nanocapsules from lab to clinic. Here we have controllably functionalized the biodegradable and widely available polysuccinimide, in order to obtain an amphiphilic poly（amino acid）. Using this polymer, we designed nanocapsules （〈 100 nm） for hydrophobic drug delivery, which could facilitate tumor targeting, hydrogen bond-based pH-responsive release, and real-time fluorescence tracking, in the second near-infrared region. This method is versatile, eco-friendly, and easy to scale up at low costs. In addition, this system can carry a cocktail of drugs, obtained by loading multiple anticancer drugs to the same vehicle. Our nanocapsules were observed to be stable in blood vessels （pH = 7.4）, and the pH-responsive release （pH = 5.0 in lysosome） was sustained. The chemotherapy results in tumor-xenografted mice suggested that our nanocapsule was safe and efficient, and may be a useful tool for drug delivery.
